. >> reporter: three years ago, this long island hospital had a problem: healthcare workers weren't cleaning their hands as often as required. >> 100,000 people die each year in the united states from hospital acquired infections. that's more than the number of people who die from breast cancer and from auto accidents. it's a huge problem, one that we want to make a dent in. >> reporter: lowering the number of infections is also good for the hospital's financial health. >> it increases length of stay. it doubles the cost of many operations. we're not reimbursed the same way that we used to for hospital-acquired infections. >> reporter: so the hospital tried an experiment. it put cameras at the entrance to patient rooms in its intensive care unit and tallied how many times workers followed hand hygiene procedures. the compliance rate w less than 10%. but once the hospital started posting the results for the shift publicly, the rate skyrocketed to over 90%. and there were other benefits: >> the patient's family-- as soon as they see us coming in and out, and when they see the hand... the activ